As is known, an exercise ball is now a common exercise equipment which can be used by a user both for physical activity with the purposes of regular training or rehabilitation and simply as a seat.
Nowadays, the need is however strongly felt to monitor the use of an exercise ball by a user, whether it is used for physical activity or simply as a seat, in order to provide the user with a useful indication, also in real time, about the use of such an exercise equipment and the results which from a physical viewpoint are obtained with such a use.